Permissions on some of the files packaged by Plesk can't be repaired: Unable to fetch deb-archive for package

Symptoms

• Plesk repair utility reports the warning messages similar to this:

  CONFIG_TEXT:   The permissions on some of the files packaged by Plesk are incorrect[ERROR]
      - WARNING: Skip checking 'plesk-php71': Unable to fetch deb-archive for package plesk-php71 (7.1.33-ubuntu.20.04.211108.1944): Command '/usr/bin/apt-get install -o Dir::Etc::sourcelist=/tmp/tmpgmm5oxay --reinstall --download-only -y plesk-php71=7.1.33-ubuntu.20.04.211108.1944'
        returned non-zero exit status 100.

• Packages mentioned in the error message have status rc in dpkg - removed, but their configuration files exist:

  # dpkg -l | grep plesk-php
  rc  plesk-php71          7.1.33-ubuntu.20.04.211108.1944          amd64        PHP scripting language for creating dynamic web sites
  rc  plesk-php71-bcmath          7.1.33-ubuntu.20.04.211108.1944          amd64        A module for PHP applications for using the bcmath library
  rc  plesk-php71-cli          7.1.33-ubuntu.20.04.211108.1944          amd64        Command-line interface for PHP

Cause

Configuration files of removed packages remain in the system. Plesk cannot repair permissions for files, if the package that supplies these files is removed. 

Resolution

1. Connect to your Plesk server via SSH.

2. Remove all rc marked packages:

   Note: In the example below, the command removes Plesk PHP packages that have rc status. Replace plesk-php with the the package name from the warning message.

   # dpkg -P --force-depends $(dpkg -l | grep plesk-php | grep "rc" | awk '{print $2}')

3. Recheck file permissions:

   # plesk sbin fsmng --check-plesk-packages